In the mountains above Thane Road, every snow storm, wind event or man-made explosion moves snow around. That means the snowpack — and the potential for avalanches — is constantly changing, too.
Avalanche specialist Pat Dryer with the Alaska Department of Transportation monitors those changes. But when he’s looking up the slopes from sea level, there’s a lot he can’t see.
“What other hazards are up there that aren’t visible from the ground?” Dryer said. “The ability to essentially fly to the top of the slope and figure that out would help.”
With drone technology, he can do just that. This winter, the state Department of Transportation launched a new project to use drones for faster, more precise avalanche monitoring along Thane Road.
Dryer and his team started experimenting with occasional drone missions last winter, and they do fieldwork trips often. But those methods are like snapshots. They capture a moment in time, and they examine just a fraction of the avalanche zone.
The new project, which is a collaboration with drone manufacturer DJI, will try to get a bigger picture with more frequent, automated drone flights.
“You can think about it kind of like a lawn mower mowing the lawn,” said Grant Hosticka, a DJI engineer who helped to launch the project. Lawnmowers cut the grass with multiple passes across the yard, patch by patch. “And drones kind of do that. But by taking photos that overlap as it goes.”
All of those photos can help avalanche specialists like Dryer map and model the snowpack using a process called photogrammetry.
“That’s taking a lot of photos and stitching them together to make a new aerial image,” Dryer said. “What we’re doing is creating a digital elevation model from the photo. In this case, it would be the total height of the snow.”
By doing this again and again over the snow season, they can understand how much snow is accumulating in avalanche start zones. That could help to estimate the size of potential avalanches, and it could inform the scheduling of the man-made avalanches that happen along Thane Road each winter.
The drone missions will be launched automatically from a new drone dock that was installed near Thane Road last month. The dock is a sleek white box — essentially a high-tech parking spot for the drone — with hook-ups for charging and remote data collection between flights.
The major advantage of the dock is that it would allow drones to take off and land without a human operator on the ground. But for now, DOT and DJI are monitoring test flights closely to work out the kinks. The goal is to learn more about the drones’ battery life, data storage and resilience to Juneau’s weather.
Only a handful of these DJI docks have been deployed in North America. Hosticka says Juneau is a great place to refine the technology.
“To be in Alaska and experience some of the tough weather, for instance,” he said. “So that the team is able to verify how it’s holding up in these conditions.”
And there are still regulatory roadblocks to overcome. The Federal Aviation Administration has not fully updated regulations for unmanned drone missions. Juneau’s avalanche specialists are working to get the permits that would allow the drone flights to be truly automatic.
Though avalanche season is wrapping up for the urban environment, Dryer said there will be plenty of time this spring to keep refining the technology.
“There’s still likely to be avalanches in the mountains for months to come,” he said. “So we’ll still use the technology and test it as best we can to learn as much as we can about it.”
By the time next year’s snow starts falling, drone missions could change the way avalanche specialists see the snowpack.
